COMMISSIONER'S DECISION
OBVIOUSNESS - Pipe Line Expansion Joint
This application claims a new pipeline expansion joint having a smooth
bore. The cited art, which showed fixed joints, did not teach nor suggest
the advance made in the art by the present application.
Final Action: Reversed
******************
This decision deals with a request for review by the Commissioner of
Patents of the Examiner's Final Action dated December 4, 1975, on
application 173,572, Class 285-29. The application was filed on June 8,
1973, and is entitled "Pipeline Expansion Joint Having A Smooth Bore."
The Patent Appeal Board conducted a Hearing on June 22, 1977, at which
Mr. R. Lafleur represented the applicant. Also in attendance was the
inventor, Mr. D.W. Bennett.
This application relates to a pipeline expansion joint having a smooth
bore, more particularly a smooth bore for use with slurries containing
solids in liquid suspension. Figure 3, shown below, is illustrative
of that arrangement:
(See Figure 1)
In the Final Action the examiner refused the application for failure to
define any patentable improvement over the following references:
Canadian Patent
301,308 June 17, 1930 Siegle
United States Patent
3,090,437 May 21, 1963 Geer
Siegle relates to pipe joints and more particularly to joints suitable
for uniting steel pipe sections in pipe lines for conveying oil and gas
and which therefore must be of such character as to prevent leakage
of the contents of the line. Figure 1, shown below, illustrates that
invention:
(see formula I)
Claim 1 of Siegle reads as follows:
In a pipe joint, the combination of a pipe section having
an integral bell at one end providing a tapered conical
surface extending inwardly from its outer face and a
gradually curved surface extending from the inner end of
the tapered surface to the cylindrical bore of the pipe,
a second section having a conical inwardly tapered zone on its
outer surface spaced from one end of the section and corres-
ponding in taper to the conical surface of the bell and a
zone between the end of the tapered zone and the end of
the section curved in correspondence with the curved surface
of the bell, said tapered and curved zones of the second
pipe section being disposed in intimate contact with
the corresponding surfaces of the bell, and welding material
disposed by autogenous welding in the angle formed between
the outer face of the bell and the peripheral surface of
the second section and serving to unite the sections.
Geer is concerned with an underwater wellhead flow line connector. Figure
4, shown below, is illustrative of that arrangement:
(see formula II)
In that action he presented his position (in part) as follows:
The two cited patents clearly show that it is well-known in
the pipeline art to provide tapered end sections of pipes on
pipe joints to reduce turbulence and friction losses. It is
considered to be obvious and mere expected skill of one
working in the art to provide the required amount of taper
for each different application of such pipe joints.
In his letter of October 6, 1975 applicant argues that "As
now recited in independent claim 1, these two small angles
are small, extend over a substantial portion of the lengths
of the respective sleeves, and are substantially equal."
Examiner maintains, as set forth in the previous Office
action that it is obvious for one skilled in the art to
provide the required amount of taper for each different
application of such pipe joint, i.e. all parameters will be
taken into consideration; diameters of the pipelines, type
of fluid to be carried, pressures, volume of flow etc....
Applicant also argues that the pipelines of the cited patents
do not carry slurries containing solids in suspension.
Examiner restates that the type of fluid to be carried is an
important factor in the design of pipelines and that this
factor is normally taken into consideration when designing
a pipeline. In a case where a pipeline does carry an
abrasive fluid, it is common knowledge of one working in the
art to provide as smooth an interior passage as possible which
would indicate small angles of taper in a telescoping joint
if such a joint was required in the pipeline.
The applicant in his response presented his views (in part) as follows:
Canadian Patent 301,308 discloses a fixed joint with no moving
parts and thus is not an expansion joint as disclosed and
claimed in the present application. This joint is for use in
pipelines conveying oils and gas and the main problems to be
solved by the joint are to prevent leakage of the content of
the line and corrosion due to sulphur and other constituents
of the fluids passing through the line. Nowhere in the patent
is there any teaching or suggestion that the joint could be
used in pipes conveying solids in suspension. Thus, this
patent is not concerned at all with applicant's problem,
i.e. excessive wear of the joint caused by turbulence in
the pipes of the solid materials in the slurry which act as
grinding stones to rapidly puncture the joint. Therefore,
the patentee of Canadian Patent 301,308, was never confronted
with the problem faced by the applicant and, of course does
not teach or suggest any solution to applicant's problem.
Furthermore, upon reading the disclosure of the patent, it
is soon realized that the critical tapered surfaces of the
patent are tapered surfaces 6 and 10 which have to meet
closely so as to form a tight joint. These tapered surfaces
cannot be compared to the critical tapered surfaces of applic-
ant's invention. The profiled portion 8 of the pipe section 1
of the patent and the chamfered portion 16 in the pipe section 2, which
in fact correspond to the critical tapered portions of applicant's
invention are not tapered portions in the common sense of the word but
rather profiled portions....
...
Concerning the Examiner's rejection on obviousness, applicant would
also like to point out that if it was so obvious to solve the
problem as the applicant has done it, why no expansion joint as
disclosed by the applicant has ever been put on the market over
the period of forth-five years since the issue of the above patent.
Solids in suspension have been carried in pipelines for a long
period of time and, as far as it is known to the applicant, no one
has ever marketed an expansion joint such as designed by the
applicant and claimed in the present application. It is to be
noted that the applicant, Grandview Industries Limited, has been
in the business of making pipes for a good number of years. If
the invention had been so obvious, it or some other organisation
would have marketed an expansion joint such as disclosed and claimed
in the present application a long time ago. As far as it is known
to the applicant, rubber hoses have been used as expansion joints
in pipes conveying solids in suspension.
...
The critical issue to be answered by the Commissioner can thus be
simply phrased. Is there any teaching in the patents of record
which would suggest to the man having ordinary skill in the art how
to solve the erosion problem occurring in expansion joints used
in pipes conveying solids in suspension? As already discussed
above, this question, in our view, must be answered in the negative
since there is no teaching nor suggestion in the prior art which
would even hint at the solution proposed by the applicant. The
prior art cited by the Examiner deals with problems which are
remote from the erosion problem faced by the applicant. Thus
these patents would generally be of no help to a man of ordinary
skill in the art in solving his erosion problem. The erosion
problem could have been caused by the accumulation of solid
materials in the joint and the deviation of the normal flow
of the liquid in the pipe which would cause friction and erosion
of the pipe. An obvious solution to this problem would be to
increase the thickness of the sleeves of the expansion joint. Even
assuming arguendo that the man skilled in the art would have
realized that the rapid wear of the pipe resulted from turbulence
in the pipe at the location where abrupt changes in diameter
exist and that consequently all sharp corners should be avoided,
it should be noted that the mere elimination of sharp corners
does not equate to the expansion joint disclosed and claimed in
the present application....
We have carefully considered the prosecution of this application and the
interesting and informative remarks made at the Hearing by Messrs. Lafleur
and Bennett. The issue before the Board is to consider whether the application
is directed to a patentable advance in the art. Claim 1 of this application
reads as follows:
A pipeline expansion joint having a smooth bore for use with
pipelines into which flow slurries containing solids in suspen-
sion comprising:
a) a first sleeve open at both ends and having a tapered portion
formed in the inner wall of one of its ends extending at a small
angle with the axis of the first sleeve and over a substantial
portion of its length from its inside diameter to substantially
its outside diameter; and
b) A second sleeve also open at both ends and having a first
portion of substantially the same inner diameter as the outer
diameter of said first sleeve and telescopically mounted on said
one end of the first sleeve, a second portion of substantially
the same inside diameter as that of said first sleeve, and an
intermediate portion expanded at a small angle with the axis
of the second sleeve over a substantial portion of its length
from said second portion to said first portion of the second sleeve,
and wherein the small angle of taper in said first sleeve is
substantially the same as the small angle of expansion in said
second sleeve, thereby providing a smooth bore throughout the
expansion joint with no area of abrupt changes in order to prevent
turbulence and the resulting wear of the expansion joint by
the solids in suspension in the slurries.
The difficulty "of how to solve the erosion problem occurring in expansion
joints used in pipes conveying solids in suspension," was clearly explained
at the Hearing. The key words may well be in expansion joints.... The
object is to avoid turbulances in the pipes which cause erosion at the joints
while being used for carrying solids in suspension. It is of course
essential that the inside diameter varies to some extent where the two pipe
sections overlap, but this variance must be accomplished with a minimum
amount of turbulance as the joint expands or contracts. This, according
to the applicant, is where the advance in the art was accomplished.
On a close study of the Siegle patent we find that he was concerned with
a fixed joint with no moving parts and thus is not an expansion joint.
Siegle was also concerned with a different problem, that of leakage in a
joint in pipe lines for conveying oils and gas. There was no consideration
of the joint being an expansive joint, nor was there any consideration of
an excessive wear of the joint caused by turbulence while carrying an abrasive
fluid. Siegle was not confronted with the problem facing the applicant,
nor, in our view, does he teach or suggest any solution which might be help-
ful to the present applicant.
Geer relates to a pipeline coupling for use in pipes conveying oil. The
coupling is not used in pipes conveying solids in suspension, and consequent-
ly the problem of erosion from abrasive fluids is not present and it
naturally follows that no solution was given. It is clearly seen that the
coupling does not show two telescopically mounted sleeves. Both of the
cited references deal with problems which are remote from the erosion prob-
lem faced by the applicant.
At first blush the cited patents may appear pertinent. At the time of the
Final Action however, the examiner did not have the advantage of the
arguments and explanations that were succinctly brought out at the Hearing.
We also find no reason to disagree with the points covered in the affidavit
from the inventor, Mr. Bennett, which was submitted to the Board after the
Hearing. These points centered around the allegation that no existing
expansion joints presently on the market are suitable for the specific purpose
of preventing erosion in expansion joints as outlined by the applicant.
In summary we are satisfied that the applicant has made a patentable advance
in the art and we recommend that the decision in the Final Action to refuse
the application be withdrawn. In reviewing the claims however, we find
that claim 1 should more distinctly define the advance in the art and be
amended to bring out the feature that the first sleeve of the expansion joint
is telescopically mounted "in continuous sliding contact" with the second
sleeve (see line 12 of claim 1).
J.F. Hughes
Assistant Chairman
Patent Appeal Board, Canada
I have studied the prosecution of this application and reviewed the
recommendation of the Patent Appeal Board. In the circumstances I withdraw
the Final Action and will accept the claims when amended as suggested by
the Board.
J.H.A. Gariepy
Commissioner of Patents
Dated in Hull, Quebec
this 8th. day of August, 1977
Agent for Applicant
Primak & Co.
240 Hymns Blvd.
Pointe Claire, Quebec
H9R 1G5